1. Field of the Invention
Embodiments of the present invention relate to camera-based head tracking in general and, in particular, to camera-based head tracking in various lighting conditions for use with 3-D video display and video game entertainment devices.
2. Description of the Related Art
Video games have become more immersive as technology progresses. Video game consoles are often produced with state-of-the-art processors, extremely fast memory, and high-end graphics cards. Input controllers have evolved from simple knobs, joysticks, and button-based controllers to accelerometer-enabled controllers that a user can swing in his or hands or wear. Further input technologies involve a camera, usually mounted on top of a television, tracking a user's body, including tracking his or her head, torso, arms, and legs. Users can control such video games by simply moving their bodies or parts thereof. For example, a player of a skateboarding game can duck down so that he or she clears an virtual bridge.
Three-dimensional (3-D, or 3D) televisions help immerse users in events happening on their display screens. For such 3-D televisions, a user sometimes dons 3-D glasses. Earlier 3-D glasses included red and blue lenses for discerning an anaglyph. Shuttered 3-D glasses have lenses that rapidly and alternatingly switch between being opaque and transparent in synchronization with a display that rapidly shows left and right images. Other types of 3-D presentation technology exist. Many are similar in that they present a separate two-dimensional image to a viewer's left eye and a separate two-dimensional image to the viewer's right eye either contemporaneously or very rapidly (e.g., at 60 Hz) in order to trick the viewer's brain into interpreting the stereoscopic images as a 3-D environment.
Video games utilizing 3-D display technologies can immerse a player in a game through the use of 3-D effects on the screen. Furthermore, video game consoles with body tracking can use 3-D effects to coordinate a player's actual movements in the real world with his or her virtual movement in a displayed virtual world. Head tracking can be critical for games that render based on where a user's head is. For example, as a user steps toward the television in his living room, a video game console can render a 3-D virtual pyre on the television so that it appears like he moves closer to it.
Thus, tracking the location, orientation, and movement of a viewer or other user's head can be important for some video games, especially those that use head-tracking to render 3-D objects closer to the user. There exists a need in the art for more robust head tracking that is not too expensive for average consumers.